This invention relates to single pressure, puffer type gas interrupters for circuit breakers, and more specifically relates to a novel nozzle construction for such interrupters which provide relief against a rapidly increasing pressure within the nozzle throat which thereafter provides for the turbulent mixing of heated gas within the nozzle with a radial blast of cold gas jets.
Single pressure puffer type gas interrupters are well known in the art. In these interrupters, a pair of contacts is separated in the region of a nozzle which directs a gas flow through the separating contacts. The gas flow is in turn produced by the relative movement of a piston and cylinder, one of which is connected to and moves with the movable contact of the interrupter. The heat of the arc drawn between the separating contacts produces a high gas pressure which acts in opposition to the operating mechanism force which moves the movable contact and pressure generating piston (or cylinder). Thus, the operating mechanism must be increased in size in order to overcome arc-generated gas pressure. This same arc-generated gas pressure is known to increase exponentially if the arc plasma blocks the nozzle throat to prevent cold gas or gas which flows from the pistoncylinder region from mixing with the arc.